Perfusion balloon catheter having a magnetically driven impeller

ABSTRACT

A balloon catheter having a perfusion lumen communicating with a blood vessel, and a magnetically driven impeller disposed in the perfusion lumen to increase blood flow through the catheter and the arteries.

BACKGROUND OF THE INVENTION

This application claims the benefit of United States Provisional patentapplication, Ser. No. 60/049,474, entitled PERFUSION BALLOON CATHETER,filed Jun. 12, 1997.

This invention relates generally to an active perfusion ballooncatheter, particularly, a catheter having a magnetically driven impellerto facilitate blood flow. Active perfusion balloon catheters may be usedin percutaneous transluminal coronary angioplasty and in other medicalprocedures to maintain blood flow through body lumens.

The need for active perfusion catheters has become more desirable withadvances in micro-surgery, neuro-surgery, interventional neuroradiology,minimally invasive coronary arterial bypass procedures, intravascularradiation for prevention of restenosis after angioplasty and stenting,and conventional angioplasty procedures.

Various perfusion catheters are known in the art including WO 95/28983;and U.S. Pat. Nos. 4,581,017; 4,909,252; 4,944,745; 5,092,844;5,163,910; 5,370,617; 5,405,383; and 5,501,667. Various catheters aredisclosed in U.S. Pat. Nos. B1 4,762,129; 5,002,531; and 5,232,445.Magnets, magnetic coupling forces, and pump systems are disclosed inU.S. Pat. Nos. 4,207,485; 4,382,245; 4,569,641; 4,717,315; 5,248,245;5,253,986; 5,609,602; 5,377,816; 5,456,134; 5,589,721; and 5,501,582. Amagnetically coupled implantable medical device is disclosed in WO95/29716.

All documents cited herein, including the foregoing, are incorporatedherein by reference in their entireties for all purposes.

SUMMARY OF THE INVENTION

Accordingly, there is a need for catheters having perfusion to maintainblood flow through body lumens during medical procedures. The activeperfusion catheter of the present invention incorporates a magneticallydriven impeller that advantageously provides blood flow to coronaryarteries temporarily blocked during balloon dilatation. The cathetershafts and components are made of plastics, polymers, or metals known inthe art.

The catheter has one or more passages for blood to reach the oppositeside of the treatment area during balloon dilatation. Blood flow may bethrough an active perfusion lumen where aperture holes and a miniatureimpeller having magnetic coupling properties actively facilitate fluidmovement. Impeller rotation is implemented by an external magneticforce. The external magnetic drive system rotates and causes acorresponding rotation of the impeller disposed in the catheter. Theimpeller may be disposed on a shaft and rotate on bearings to minimizefrictional forces.

Blood may also flow through a passive perfusion lumen where apertureholes and system pressure allows blood to flow through the guidewirelumen to regions proximal or distal of the balloon. Passive perfusionmay occur through a guidewire lumen as blood enters through one or moreapertures in the wall of the shaft. The apertures are located proximalof the balloon, and system pressure drives blood longitudinally throughadditional perfusion openings or apertures. The active and passiveperfusion systems may be used in combination.

The external magnetic drive system may be contained in an enclosure andinclude an electrical or battery power source. The enclosure providescontainment and protection of the drive system and may be placed on thepatients body adjacent an area in the body where the impeller of thecatheter is disposed.

The drive system includes a magnet or magnetic surface which rotatesabout an axis. The drive system may be powered by a motor and include anon-off switch, variable speed control, and various control systems tomeasure and monitor the rotation of the magnetic surface and thecorresponding blood flow through the catheter. Also, controls maymeasure the strength of the magnetic coupling of the magnetic surfaces,and the rotational speed of the impeller. The magnetic drive systemincludes magnetic flux properties capable of transmitting sufficientmagnetic forces to the magnetic impeller and for magnetic coupling tooccur.

The impeller may be located in a portion of the catheter intended to bedisposed in the ascending aorta which generally allows the catheter tohave a larger impeller. Accordingly, the impeller is preferably locatedabout six inches proximal of the balloon.

In sum, the invention relates to a perfusion balloon catheter includinga first shaft having proximal and distal portions, a wall, one or morefirst apertures through the wall, a balloon disposed on the shaft distalof the first apertures, an inflation lumen in communication with theballoon, and a perfusion lumen in communication with the firstapertures. At least one impeller is disposed in the perfusion lumen. Theimpeller has a predetermined shape and one or more magnets disposedthereon. The magnets magnetically couple with a magnetic source causingrotation of the impeller. Rotation of the impeller may convey fluidthrough the perfusion lumen. The perfusion balloon catheter may furtherinclude a second shaft disposed in the first shaft, through theimpeller, and extend distal thereof. The second shaft has proximal anddistal portions and a wall. The wall has one or more apertures in thedistal portion of the second shaft, and one or more apertures distal ofthe impeller. A perfusion lumen is disposed in the second shaft betweenthe apertures and is in communication therewith. The impeller may belocated distal of the first apertures. The impeller may be disposedunder a portion of the balloon. The impeller may be made of metal,ceramic, or polymeric material. The impeller may include at least onespiral-shaped groove. The impeller may include one rib, thread, orscrew. The impeller may operate like an archimedes screw. The perfusionballoon catheter may further include an external magnetic drive systemadapted to provide a magnetic field to a vicinity of the magnets on theimpeller. The external magnetic drive system may be powered by a sourceincluding a battery, electricity, magnetic coupling, or combinationthereof. The impeller may further include a plurality of magnetsdisposed thereon to collectively form a continuous spiral magnet. Theimpeller may include a plurality of magnets disposed side-by-side toform a generally continuous magnetic thread. Each magnetic thread has anopposite magnetic polarity at its outer extremity to its adjacentmagnetic thread. The impeller rotates by exposing at least one magneticthread to successive magnetic drive magnets of the opposite polarityupon rotation of the magnetic drive system. Successive magnetic couplingbetween the magnetic threads and the successive magnets on the magneticdrive system causes rotation of the impeller. The perfusion ballooncatheter may further include an external magnetic drive system includinga magnetic surface adapted to generate a magnetic field to one or moremagnets disposed on a component connected to the impeller causing amagnetic coupling and rotation of the impeller.

The invention also relates to a perfusion catheter system including acatheter having proximal and distal ends, one or more lumens, and anelongated impeller having proximal and distal ends disposed in one ofthe lumens. One or more magnets are disposed on the impeller or acomponent connected to the impeller. The impeller magnetically coupleswith a magnetic drive system, rotates, and moves fluid through thecatheter. The catheter is disposed in a body lumen for treatment. Themagnetic drive system is external to the catheter and has one or moremagnets that rotate about an axis and convey a magnetic field to the oneor more magnets disposed on the impeller. The impeller may move fluid ina predetermined direction when rotated.

The invention also relates to a method of actively perfusing bloodthrough a catheter including inserting a shaft into an artery. The shafthas proximal and distal portions, a wall, one or more first and secondapertures in the wall, and at least one perfusion lumen disposed thereinbetween the first apertures and the second apertures and incommunication with the first and second apertures. The perfusion lumenhas at least one elongated magnetic member rotatably disposed therein.Rotating the member using an external magnetic force causes the impellerto convey fluid into one of the first or second apertures, through theperfusion lumen, and out the other of the first or second apertures uponapplication of a magnetic force.

The invention also relates to a perfusion catheter system including adrive system including an elongated shaft having at least one magneticsurface including one or more first magnets disposed thereon. Themagnetic surface adapted to rotate and be disposed on or adjacent a bodysurface. The catheter is less than about 15 French in size, has proximaland distal ends, one or more lumens longitudinally disposed therein, oneor more supports mounted in the lumen, and an elongated impeller havingone or more second magnets disposed thereon. The drive system is adaptedto rotate causing successive magnetic coupling between the first magnetsand the second magnets and rotation of the impeller. The first magnetsmay be magnetically attracted to the second magnets of the oppositepolarity and magnetically couple. The rotation of the magnetic surfacemay expose the second magnets to different first magnets of the oppositepolarity which are disposed further along the length of the magneticsurface such that the second magnets are magnetically coupled todifferent first magnets as the shaft rotates causing the impeller torotate and fluid to move in the catheter.

The invention also relates to a method of actively perfusing bloodthrough a catheter comprising the steps of inserting a shaft into a bodylumen. The shaft having proximal and distal portions, a wall, one ormore first apertures in the wall, and at least one perfusion lumendisposed distal of the first apertures and being in communicationtherewith. The perfusion lumen has at least one impeller disposedrotatably therein. The impeller has one or more magnets disposed thereonand is adapted to rotate and convey blood through one of the firstapertures and through the perfusion lumen upon application of a magneticforce thereto; applying a magnetic field to the impeller from externalthe body lumen; and causing magnetic coupling and rotation of theimpeller using the magnetic field. The method may include using animpeller including a plurality of magnets disposed generallyside-by-side to form a generally continuous magnetic thread. Eachmagnetic thread has an opposite magnetic polarity at its outer extremityto its adjacent magnetic thread. The method may further include the stepof exposing at least one magnetic thread to successive magnetic drivemagnets of the opposite polarity by rotating the magnetic drive so thatsuccessive magnetic coupling between the magnetic thread and thesuccessive magnetic drive magnets rotates the impeller.

Still other objects and advantages of the present invention and methodsof construction of the same will become readily apparent to thoseskilled in the art from the following detailed description, wherein onlythe preferred embodiments are shown and described, simply by way ofillustration of the best mode contemplated of carrying out theinvention. As will be realized, the invention is capable of other anddifferent embodiments and methods of construction, and its severaldetails are capable of modification in various obvious respects, allwithout departing from the invention. Accordingly, the drawing anddescription are to be regarded as illustrative in nature, and not asrestrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a side view of a perfusion balloon catheter;

FIG. 2 illustrates a side view of another embodiment of the perfusionballoon catheter;

FIG. 3 illustrates a cross-sectional view of an embodiment of thecatheter;

FIG. 4 illustrates a cross-sectional view (excluding balloon) takenalong the line 4--4 of FIG. 2;

FIG. 5 illustrates a view of an embodiment of an impeller disposed in acatheter lumen;

FIG. 6 illustrates a view of an embodiment of an external magnetic drivesystem disposed over an impeller in a catheter in a body lumen;

FIGS. 7a-c illustrates views of several embodiments of magnetic surfacepatterns of the external magnetic drive system of FIG. 6;

FIG. 8 illustrates a view of an embodiment of an external magnetic drivesystem disposed over an impeller in a catheter in a body lumen;

FIG. 9 illustrates a view of an embodiment of an external magnetic drivesystem disposed over a catheter component in a body lumen; and

FIGS. 10a-b illustrates views of several embodiments of impellers(threads not shown) having magnets disposed in the substrate in variouspatterns.

FIG. 11 illustrates a view of an external magnetic drive systemsuperimposed over an impeller disposed in a catheter (not shown) in abody lumen;

FIG. 12 illustrates a side view of the external magnetic drive systemhaving a magnetic surface;

FIG. 13 illustrates a bottom view of the magnetic surface of FIG. 12having alternating polarity;

FIG. 14 illustrates a cross-section of an impeller showing magnetizedhelical threads with north and south polarity disposed in anon-magnetized substrate or shaft;

FIG. 15 illustrates a side view of an impeller with threads havingalternating polarity;

FIG. 16 illustrates a rapid exchange embodiment of the perfusioncatheter;

FIG. 17 illustrates a cross-sectional view of the catheter of FIG. 16showing a balloon inflation lumen, rapid exchange lumen, and activeperfusion lumen;

FIG. 18 illustrates a coaxial to bitumen embodiment of the perfusioncatheter having lumens, aperture, impeller, balloon, and guidewire; and

FIG. 19 illustrates a cross-sectional view of the catheter of FIG. 18illustrating a contrast lumen, guidewire lumen and perfusion lumen.

DETAILED DESCRIPTION OF THE INVENTION

The perfusion balloon catheter 10 may include rapid-exchange, over-thewire, or fixed wire embodiments. Reference is made to FIGS. 1 and 2which illustrate the distal portion of two embodiments of the perfusionballoon catheter 10 having active perfusion, passive perfusion, orcombinations of both characteristics. Various sizes and embodiments ofthe catheter 10 in about the 3 French to 34 French range are envisioned.The impeller 30 may be located proximal of the balloon 20 which wouldallow a relatively larger diameter impeller 30 disposed in the catheter10.

FIG. 1 illustrates the distal portion of a catheter 10 having an outsideshaft 12 and an inside shaft 14. Secured between the outside shaft 12and the inside shaft 14 may be a flow block 16 to prevent blood flow tothe proximal portion of the catheter 10. One or more proximal apertures18 are located proximal of the impeller 30 and extend through the wall19 of the outside shaft 12 to allow blood to flow to the activeperfusion lumen 24 and through the impeller 30. The impeller 30 isdisposed on bearings 33 and rotates when successive magnetic orelectromagnetic forces are applied and after successive magneticcoupling occurs. Successive magnetic coupling provides sufficient torqueto rotate the impeller 30 at a desired speed to move the blood throughthe catheter 10. For example, as the impeller 30 is rotated, blood maybe forced distally through the impeller 30 to a distal perfusion opening26 or a distal aperture 18 (not shown) located distal of the balloon 20.An inflation lumen 22 is disposed in the catheter 10 which communicateswith the balloon 20. The inflation lumen 22 may run through the shaft ofthe impeller 30, or the inflation lumen 22 may be a dedicated lumenextruded in the catheter 10. A tip 28 may be connected to one of theshafts 12, 14 at the distal end of the catheter 10.

FIG. 2 illustrates an over-the-wire embodiment of the catheter 10including an outside shaft 12 and an inside shaft 14. An inflation lumen22 is disposed in the catheter 10 and communicates with the balloon 20.Secured between the outside shaft 12 and the inside shaft 14 may be aflow block 16 (not shown). One or more proximal apertures 18 are locatedproximal of an impeller 30 and extend through the wall 19 and allowblood to flow into the active perfusion lumen 24 and into the impeller30 or into the guide lumen 23. When successive magnetic forces areapplied to the impeller 30, rotation occurs, and blood or fluid is movedthrough passages and the catheter 10. Apertures 21 are provided throughthe wall of the inside shaft 14 into the guide lumen 23. A tube 15 madeof a material such as Nitinol, having an inside diameter dimension ofabout 0.013 inches and an outside diameter of about 0.016 inches mayextend distally from the distal end of the inside shaft 14 for a lengthof about 0.500 inches. The impeller 30 may be disposed on the tube 15and bearings 33. Preferably, frictional forces are minimal between theimpeller 30 and bearings 33, and the impeller 30 and the catheter shaft12. The impeller 30 has threads which force fluid in a predetermineddirection upon rotation. The size and pitch of the threads provide apredetermined flow at a certain rotational speed.

FIG. 3 illustrates a cross-sectional view of an embodiment of a trilumencatheter 10. In one embodiment, radius R1 is about 0.011 inches, radiusR2 is about 0.020 inches; diameter D1 is about 0.016 inches; anddiameter D2 is about 0.047 inches.

FIG. 4 illustrates a cross-sectional view of a trilumen catheter 10ataken along line 4--4 in FIG. 2. In one embodiment, diameter D3 is about0.031 inches, and diameter D4 is about 0.037 inches.

FIG. 5 illustrates an embodiment of an impeller 30 having a helicaldesign which is disposed in the perfusion lumen 24 of the catheter 10.The impeller 30 may be an archimedes screw design with spiral threads orscrew shapes. The impeller 30 may include a tube bent spirally around anaxis or include a broadthread. The impeller 30 may be made of metal,ceramic, or polymeric materials and be machined or molded to a desiredshape. The impeller 30 is preferably made of a flexible polymericmaterial adapted for tortuous passage through arteries. The shaft 14 ortube 15 may have protrusions (not shown) which allow rotation, butprevent substantial longitudinal displacement of the impeller 30. Theimpeller 30 may also have adjustments (not shown) to prevent rotation ina certain direction.

Reference is made to FIG. 6 showing an embodiment of an externalmagnetic drive system 50 which includes a power source (not shown) and amagnetic surface 42 having magnets 44 disposed therein in predeterminedpatterns. The magnetic drive system 50 is shown disposed over anembodiment of the impeller 30 in a catheter 10, in a body lumen, under abody surface 47. Various patterns and sizes of magnetic polarity areincorporated on or in the magnetic surface 42 for magnetic coupling.Certain patterns and sizes such as shown in FIGS. 7a-7c may assist withthe alignment of the lead angle of the magnetic surface 42 to the leadangle of the magnets 46. As shown in FIGS. 8 and 9, the magnetic surface42 magnetically couples with magnets 46 disposed on he component 31which is rotatably connected to the impeller 30. The impeller 30 ay bemounted on a metal support shaft 15 or on shaft 14. Supports 35 may beused to support portions of the impeller 30.

In operation, the magnetic surface 42 is activated and rotated in alinear or rotational motion on a patients body in the vicinity of theimpeller 30 and the magnetic forces are used to provide rotationalmotion of the impeller 30. Rotation of the magnetic surface 42 creates amagnetic field which causes magnets 46 in the catheter 10 to attempt toorient with the magnets 44, 54 of the magnetic surface 42. Thesuccessive attempts of the magnets 46 to orient with magnets 44, 54causes the impeller 30 to rotate. The magnets 44 54 are of sufficientmagnetic strength or flux to cause the impeller 30 to rotate. When themagnetic surface 42 is deactivated or removed from the patient's body,the successive magnetic couplings no longer occur, and rotation of theimpeller 30 stops. Accordingly, fluid may be drawn through the variousapertures into the perfusion lumen 24 and out the other apertures. Themagnetic surface 42 is preferably rotated in a plane parallel to thelongitudinal axis of the impeller 30.

FIGS. 10a-b illustrate several embodiments of magnets 46 disposed invarious patterns on or in the substrate of an impeller 30 (threads orappendages not shown on impeller). The magnets 46 may be disposed on orin the impeller 30 in a spiral pattern having a constant lead angle overthe length of the impeller 30. The magnets 46 may be disposed inparallel rows or in a staggered pattern. Magnets 44 may be disposed inthe magnetic surface 42 in a pattern duplicative of the lead angle ofthe magnets 46 in the impeller 30. The magnets 46 may be spaced apart orin strips. Additional patterns are envisioned.

FIG. 11 illustrates a magnetic surface 42 superimposed over an impeller30 which is disposed in a catheter (not shown) in a body vessel. Theback of the magnetic surface 42 has opposite polarity. The magneticsurface 42 shown is made of 4 quadrants of magnetic material. The faceof the magnetic surface 42 oriented toward the impeller is made ofwedges that alternate north and south in polarity. The preferred axis ofthe magnetic surface 42 shown is about 90 degrees to the axis of theimpeller 30. The impeller 30 may be quartered into alternating north andsouth polarities which run along the longitudinal axis of the impeller30. The substrate of the impeller 30 may be magnetized and the threadsmay not be magnetized. When the magnetic surface 42 rotates, theexternal north magnet engages the internal south magnet, and theexternal south magnet engages the internal north magnet resulting inrotation of the impeller 30.

FIG. 12 illustrates a side view of an embodiment of a magnetic drivesystem 50 magnetic surface 42 having alternating north and south magnetsembedded in the bottom surface.

FIG. 13 illustrates a bottom view of the magnetic surface 42 of FIG. 12showing the alternating north and south polarized magnets.

FIG. 14 illustrates a cross-sectional view of an end of the impeller 30having two magnetic threads which are helically disposed about anon-magnetized substrate or shaft. The substrate is not magnetized andthe threads are magnetized. Continuous threads of magnetized material(north or south) extend from the substrate. One thread is magnetizednorth and the other thread is magnetized south. The external northmagnet of a magnetic surface 42 magnetically couples with the internalsouth magnets of the impeller 30 and the external south magnetmagnetically couples with the internal north magnet.

FIG. 15 shows a side view of an impeller 30 having threads withalternating polarity.

FIG. 16 illustrates a rapid exchange embodiment of the perfusioncatheter 10 having trilumens, apertures, impeller, balloon, andguidewire.

FIG. 17 illustrates a cross-section of the catheter 10 of FIG. 16showing a balloon inflation lumen, rapid exchange lumen, and activeperfusion lumen.

FIG. 18 illustrates a coaxial to bitumen embodiment of the perfusioncatheter 10 having lumens, apertures, impeller, balloon, and guidewire.Ports for contrast used to inflate the balloon are located on the otherside from the segment for the guidewire. The contrast lumen is pluggedat the distal portion of the catheter 10.

FIG. 19 illustrates a cross-section of the catheter 10 of FIG. 18showing a contrast lumen, guidewire lumen and perfusion lumen.

It will be evident from considerations of the foregoing that theperfusion balloon catheter is now available, and may be constructedusing a number of methods and materials, in a wide variety of sizes andstyles for the greater efficiency and convenience of a user.

The above described embodiments of the invention are merely descriptiveof its principles and are not to be considered limiting. Furthermodifications of the invention herein disclosed will occur to thoseskilled in the respective arts and all such modifications are deemed tobe within the scope of the invention as defined by the following claims.

What is claimed is:
 1. A perfusion balloon catheter comprising:a firstshaft having proximal and distal portions, a wall, one or more firstapertures through the wall, a balloon disposed on the shaft distal ofthe first apertures, an inflation lumen in communication with theballoon, and a perfusion lumen in communication with the firstapertures; at least one impeller disposed in the perfusion lumen, theimpeller having a predetermined shape and one or more magnets disposedthereon, the magnets adapted to magnetically couple with a magneticsource spaced away from the perfusion balloon catheter and adapted tocause rotation of the impeller and a second shaft disposed in the firstshaft, through the impeller, and extending distal thereof, the secondshaft having proximal and distal portions and a wall, the wall havingone or more apertures in the distal portion of the second shaft, and oneor more apertures distal of the impeller, a perfusion lumen disposed inthe second shaft between the apertures and being in communicationtherewith.
 2. The perfusion balloon catheter of claim 1 wherein rotationof the impeller conveys fluid through the perfusion lumen.
 3. Theperfusion balloon catheter of claim 1 wherein the impeller is locateddistal of the first apertures.
 4. The perfusion balloon catheter ofclaim 1 wherein the impeller is disposed under a portion of the balloon.5. The perfusion catheter system of claim 1 wherein the impeller is madeof at least one of metal, ceramic, or polymeric material.
 6. Theperfusion catheter system of claim 1 wherein the impeller includes atleast one spiral-shaped groove.
 7. The perfusion balloon catheter ofclaim 1 wherein the impeller includes at least one rib, thread, orscrew.
 8. The perfusion balloon catheter of claim 1 wherein the impelleris adapted to operate like an archimedes screw.
 9. The perfusion ballooncatheter of claim 1 further comprising an external magnetic drive systemadapted to provide a magnetic field to a vicinity of the magnets on theimpeller.
 10. The perfusion balloon catheter of claim 1 wherein theimpeller further comprises a plurality of magnets disposed thereon tocollectively form a continuous spiral magnet.
 11. The perfusion ballooncatheter of claim 1 wherein the impeller includes a plurality of magnetsdisposed side-by-side to form a generally continuous magnetic thread,each magnetic thread having an opposite magnetic polarity at its outerextremity to its adjacent magnetic thread, the impeller adapted torotate by exposing at least one magnetic thread to successive magneticdrive magnets of the opposite polarity upon rotation of the magneticdrive wherein successive magnetic coupling between the magnetic threadand the successive magnetic drive magnets rotates the impeller.
 12. Theperfusion balloon catheter of claim 1 further comprisingan externalmagnetic drive system including a magnetic surface adapted to generate amagnetic field to one or more magnets disposed on a component connectedto the impeller causing a magnetic coupling and rotation of theimpeller.
 13. The perfusion balloon catheter of claim 12 wherein theexternal magnetic drive system is powered by a source selected from abattery, electricity, magnetic coupling, or combination thereof.
 14. Aperfusion catheter system comprising:a drive system comprising anelongated shaft having at least one magnetic surface comprising aplurality of first magnets disposed thereon, the magnetic surfaceadapted to rotate and be disposed on or adjacent a body surface; acatheter less than 15 French in size having proximal and distal ends,one or more lumens longitudinally disposed therein, one or more supportsmounted in the lumen, and an elongated impeller having one or moresecond magnets disposed thereon; and the drive system adapted to rotatecausing successive magnetic coupling between the first magnets and thesecond magnets and rotation of the impeller.
 15. The perfusion cathetersystem of claim 14 wherein the first magnets are magnetically attractedto the second magnets of the opposite polarity and magnetically couple,the rotation of the magnetic surface exposing the second magnets todifferent first magnets of the opposite polarity which are disposedfurther along the length of the magnetic surface, such that the secondmagnets are magnetically coupled to different first magnets as the shaftrotates causing the impeller to rotate and fluid to move in thecatheter.
 16. A method of actively perfusing blood through a cathetercomprising the steps of:inserting a shaft into a body lumen, the shafthaving proximal and distal portions, a wall, one or more first aperturesin the wall, and at least one perfusion lumen disposed distal of thefirst apertures and being in communication therewith, the perfusionlumen having at least one impeller disposed rotateably therein, whereinthe impeller includes a plurality of magnets disposed generallyside-by-side to form generally continuous magnetic thread, each magneticthread having an opposite magnetic polarity at its outer extremity toits adjacent magnetic thread, the impeller adapted to rotate and conveyblood through one of the first apertures and through the perfusion lumenupon application of a magnetic force thereto; and applying a magneticfield from a magnetic drive system external to the impeller and the bodylumen by exposing at least one magnetic thread to successive magneticdrive magnets of the opposite polarity by rotating the magnetic drive sothat successive magnetic coupling between the magnetic thread and thesuccessive magnetic drive magnets rotates the impeller.
 17. A perfusionballoon catheter comprising:a first shaft having proximal and distalportions, a wall, one or more first apertures through the wall, aballoon disposed on the shaft distal of the first apertures, aninflation lumen in communication with the balloon, and a perfusion lumenin communication with the first apertures; and at least one impellerdisposed in the perfusion lumen, the impeller having a predeterminedshape and one or more magnets disposed thereon, wherein the magnets aredisposed side-by-side to format generally continuous magnetic thread,each magnetic thread having an opposite magnetic polarity at its outerextremity to its adjacent magnetic thread, the impeller adapted torotate by exposing at least one magnetic thread to successive magneticdrive magnets of the opposite polarity upon rotation of the magneticdrive wherein successive magnetic coupling between the magnetic threadand the successive magnetic drive magnets rotates the impeller.